Knitting machine stitch length control



o. w. HOLDER 3,013,417

KNITTING MACHINE STITCH LENGTH CONTROL 2 Sheets$heet 1 Dec. 19, 1961Filed Jan. 13, 1959 N 1 I 10 m N N INVENTOR:

| 0115 W. HOLDER.

"' BY g agwrw A'ITORNEY5 Dec. 19, 1961 o. w. HOLDER 3,013,417

KNITTING MACHINE STITCH LENGTH CONTROL Filed Jan. 13, 1959 2Sheets-Sheet 2 W42. 5 9O S 74' INVENTOR. O'ns W. HOLDER Y z% MM+%ATTORNEYS n t States Patent 3,013,417 MAC STITCH LENGTH CONTROL Otis W.Holder, Mount Airy, N.C., assignor to Patent- Hose Corporation,Burlington, N.C., a corporation of North Carolina Filed Jan. 13, 1959,Ser. No. 786,634 5 Claims. (Cl. 66-54) This invention relates generallyto a novel mechanism and method for regulating the length of stitchesformed by the needles of a circular independent needle hosiery knittingmachine.

For many years the stitch length has been controlled by varying therelationship between the needle cylinder and the stitch forming cams andthis system is presently used by the two most popular types of circularindependent needle knitting machines. In Scott & Williams machines, asshown in United States Patent No. 1,152,850, dated September 7, 1915,the needle cylinder is raised and lowered by pattern control means toraise and lower a tube positioned in alinement below the needle cylinderwhile maintaining the stitch forming cams in a stationary position. InHemphill machines, as shown in United States Patent No. 933,443, datedSeptember 7, 1909, the stitch forming cams are raised and lowered bypattern control means while maintaining the needle cylinder in astationary position. By changing the vertical relationship betweentheneedle cylinder and the stitch cams, the depth to which the needlesare drawn each time that the butts thereof are lowered by the stitchcams is also changed to thus control the length or size of stitchesdrawn by the needles.

In both of these types of knitting machines the needles are carried forindependent vertical movement in the needle cylinder and when therelative position of the needle cylinder and the stitch forming cams ischanged, the normal path of travel of the butts is also changed. Thus,the vertical position of needle butts passing through and about to enterthe stitch cams will be changed when the stitch length is changed byimparting relative movement between the needle cylinder and the stitchcams. If the vertical position of the needle butts, in relation to thestitch cams, is changed too drastically, the butts will engage the endsof the stitch cams and be broken 01f instead of engaging the inclinedsurfaces and being raised or lowered. In both of the present types ofknitting machines, it is impossible to suddenly increase or decrease thesize of stitch being drawn by vertical movement of either the needlecylinder or the stitch drawing cam without breaking the butts ofneedles.

The types of stitch regulating mechanisms presently in use are limitedto a gradual increase and decrease in stitch length regulation and arealso limited to a relatively narrow range of stitch length regulation.The range of stitch length regulation is limited when vertical movementis imparted to the stitch cams because the relationship between thehooks of the needles and the yarn feeding point is changed and the yarnwill not be fed to the needles at the desired position. Because theconventional knitting machines are limited to a narrow range of stitchlength regulation and to a gradual change in stitch length adjustment,several methods have been proposed for modifying these machines toprovide auxiliary means for drawing unusually long stitches. One methodincludes changing the radial movement of the sinkers so that they aremoved in earlier than usual whereby the yarn will be fed over the nibsthereof to thus form longer than usual stitches. However, when drawinglonger stitches by knitting over the nib or high portion of the sinker,the sinkers cannot carry out their usual function of holding down thefabric and this frequently results in smash-ups and an accumulation offabric, thus causing broken needle hooks, latches, butts and the like.

In some cases the machines have been modified to include means to raisethe inner ends of the sinkers when yarn is fed to the needles andstitches drawn to thus increase the amount of yarn present in eachstitch loop. The sinkers are usually positioned horizontally and whenthe inner ends of the sinkers are raised it is extremely diflicult toaccurately control their radial position and maintain the same at afixed level.

With the foregoing remarks in mind, it is the primary object of thisinvention to provide a novel mechanism and method for regulating thestitch length of a circular knitting machine within a wide range ofregulation while maintaining the sinkers in a horizontal position andmoving them radially in a conventional path.

It is another object of this invention to provide a stitch regulatingmechanism which may be operated to quickly change the length of stitchbeing formed from a very short stitch to a very long stitch and viceversa without changing the vertical relationship between the needlecylinder and the stitch cams.

It is another object of this invention to provide an improved stitchregulating mechanism for controlling the length of stitch formed bycircular knitting machines whereby the operation of the regulatingmechanism will not change the operating relationship of the needlecylinder and stitch cams and thereby reduce needle butt breakage.

It is another object of this invention to provide a stitchregulatingmechanism which is controlled by the usual pattern control mechanism ofthe knitting machine and which is operative to vary the relativeposition of the sinkers to the hooks of the needles while maintainingthe same operative relationship between the path of travel of the needlehooks and the yarn feeding fingers as well as between the path of travelof the needle butts. and the stitch cams.

Some of the objects of the invention having been stated, other objectswill appear as the description proceeds when taken in connection withthe accompanying drawings, in which FIGURE 1 is a fragmentary left-handside elevation of a circular knitting machine with parts broken away forpurposes of clarity and with the present invention applied thereto;

FIGURE 2 is an enlarged vertical sectional view through the upperportion of the machine, taken substantially along line 22 in FIGURE 1;

FIGURE 3 is an enlarged fragmentary viewof the right-hand portion ofFIGURE 2 with the central portion broken away and showing the'relationship of the sinkers and needle cylinder when the machine isforming regular or short stitches;

FIGURE 4 is a view similar to FIGURE 3 but showing the relationship ofthe sinkers and needle cylinder when the machine is forming longstitches;

FIGURE 5 is a horizontal sectional view at a reduced scale and beingtaken substantially along the line 55 in FIGURE 2 (at a reduced scale).

Referring to the drawings, it will be noted that the present stitchregulating control is illustrated as being applied to a Scott & Williamstype plain knitting machine and it is to be understood that thismechanism could also be applied to Hemphill type machines and to other.types of Scott & Williams machines, such as those havof a mating bevelgear 12 mounted for rotation in a cam bed plate 13. The cam bed plate 13is suitably supported on the frame and supports a latch ring pivot post14 (FIGURE 1) and a widening pick stand 16 as well as the usual needlecams and stitch cams 17 positioned around the needle cylinder 20.

The outer surface of the needle cylinder 20 is provided with a pluralityof grooves which extend vertically and receive latch needles N forvertical sliding movement therein. The lower surface of the cam bedplate 13 is provided with a downwardly extending flange 25 in which theupper end of a tube 30 is mounted for vertical sliding movement. Thetube 30 is commonly known as a cylinder raising tube but which in thisinstance will be called a sinker raising tube for purposes to be laterexplained. The lower end of the sinker raising tube 30 is suitablymounted for vertical movement in a bracket carried by the frame 10 in aconventional manner, not shown.

The sinker raising tube 30 is provided with a support bracket 31 whichis fixed on the tube 30 and which is normally supported on the upper endof a screw 32 threadably supported at its lower end in an arm of astitch length adjusting lever 33. One end of the lever 33 isoscillatably mounted on a shaft 34 and the other end of the lever 33 issupported on suitable cams, not shown, fixed on a main pattern drum 35.The pattern drum 35 is mounted for rotation in the frame 10 on a shaft36 and is driven in a step-by-step manner through conventional gearingunder control of the main pattern chain, not shown.

The main pattern drum 35 also controls other conventional parts of theknitting machine, such as thrust rods 40 which extend upwardly therefromand control the operation of yarn fingers 41 mounted in a latch ring 42.It will be noted in FIGURE 1 that the rear portion of the latch ring 42is pivotally mounted on the upper end of the post 14 as at 43 and thefront portion is supported on the upper end of the stand 16. Theknitting machine is also provided with a sinker head, broadly indicatedat 50, which is spaced below the latch ring 42 and supported in a mannerto be later described. A sinker head hold-down arm 52 is suitablysecured at its lower end to the sinker raising tube 30 and its upper endextends over the sinker head 50 and engages the same to hold the sinkerhead 50 in fixed relation with the sinker raising tube 30.

The parts heretofore described are conventional parts of a Scott &Williams type knitting machine and it is with this type of machine thatthe present invention is illustrated, although it is to be understoodthat this invention may be applied to other types of knitting machines.In the conventional knitting machine of this type, the sinker head 50 isfixed on the upper end of the needle cylinder 20 and the needle cylinder20 is mounted for vertical movement on an upstanding sleeve which isintegral with the gear 12. Vertical movement of the sinker head 50, tovary the length of stitch drawn by the needles N, is effected by pinswhich are mounted for vertical sliding movement through the gear 12. Theupper ends of these pins engage the lower surface of the needle cylinder20 and the lower ends of the pins are supported on the upper end of thetube 30. Thus, when the sinker raising tube 30 is raised or lowered, theneedle cylinder 20 will be correspondingly raised and lowered on thegear sleeve to thus raise and lower the sinker head 50.

Since the needle cylinder 20 must be moved vertically in order to raiseand lower the sinker head 50, the needles N carried by the needlecylinder 20 will also be moved vertically thereby changing their normalrelationship with the stitch cams, which remain stationary. Theoperating butts of the needles N follow a certain path of travel throughthe stitch cam and any drastic vertical movement of these needle buttswill cause the butts to be raised or lowered so that they do notproperly engage the stitch cams and are broken.

By the use of the present invention, it is not necessary to raise orlower the needle cylinder 20 in order to raise or lower the sinker head50 and change the stitch length. In the present invention, the lower endof the needle cylinder 20 is fixed to the bevel gear 12 as by screws 55(FIGURES 2, 3 and 4) so that the needle cylinder 20 will at all timesremain in a stationary vertical position and thus, the needles N willalways maintain the same relationship with the stitch cams 17 and theyarn feeding fingers 41.

In the present instance, the upper end of the sinker raising tube 30 isprovided with a bearing ring 56 on which the lower end of a sinkersupport sleeve 57 is supported for rotation. The upper end of the sleeve57 has an enlarged annular flange 60 formed integral therewith andhaving suitable radial grooves or slots 61 in vertical alinement abovethe needle slots in the needle cylinder 20 to provide a passageway forthe needles N therethrough (upper right-hand portion of FIGURE 2). Theouter periphery of the flange 60 supports a sinker bed 65 which isremovably secured to the flange 60 by set screws 66 adapted to bearagainst the outer ends of pins 67. The upper surface of the sinker bed65 is provided with radially extending sinker grooves or slots 70 forslidably supporting the outer ends of sinkers S. The inner ends of thesinkers S are supported for radial sliding movement in the grooves of asinker ring 72 which is suitably fixed on the upper inner surface of thesleeve 57.

A sinker cap 74 holds the sinkers S in the sinker bed 65 and ring 72 andhas conventional sinker operating cams, not shown, which cause thesinker to move inwardly and outwardly in the sinker bed 65 and betweenthe needles N as they pass through the knitting wave, in a conventionalmanner. The front portion of the sinker cap 74 is provided with cars 75(FIGURE 1) which are adapted to abut against opposite sides of the upperend of the stand 16 to prevent rotation of the sinker cap 74.

Relative rotation between the sleeve 57 and the needle cylinder 20 isprevented by a key which is fixed in the sleeve 57 and engages a keyway81 cut in the inner surface of the needle cylinder 20. Thus, whenrotation or reciprocation is imparted to the bevel gear 11, like motionwill be imparted to the bevel gear 12, needle cylinder 20, sleeve 57 andsinker bed 65 so that the needles N and sinkers S rotate or reciprocatein a conventional manner. The sinker cap 74 will remain in substantiallya stationary position and the sinker cams carried hereby will controlradial or inward and outward movement of the sinkers relative to theneedles N.

In order that the sinker head 50 may be lowered to a position below thatshown in FIGURES 2 and 3, the flange 60 of the sleeve 57 is undercut asby an annular groove 85. Thus, if the sleeve 57 is lowered far enough,the upper end of the needle cylinder 20 can extend into the annulargroove 85. The sinker head hold-down arm 52 insures that any verticalmovement imparted to the tube 30 will also be imparted to the sinkerhead 50 since the lower end of the arm 52 is attached to the tube 30 andthe upper end of the tube 30 bears down against the upper surface of thesinker head 50.

In the present invention, it is not necessary to vertically move theneedle cylinder when the stitch length is being regulated and thereforethe operating butts of the needles N maintain their usual relationshipwith the stitch drawing cams. Thus, the stitch cams always draw theneedles down the same distance regardless of the side stitch loops beingformed while the size of the stitch loops is controlled by raising orlowering the sinker raising tube 30 by means of cams on the main patterndrum 35 and the stitch regulating lever 33.

As is well known, the hooks of the needles N receive the yarn from theyarn feeding fingers 41 and the needles are lowered by the stitch camsso that stitches are formed over the throat portion 90 of the sinkers.If the sinkers are raised, more yarn will he used in each stitch loopdrawn by the needles and conversely, if the sinkers are lowered, lessyarn will be used in each stitch loop. Relatively short stitch loopswill be formed when the sinker head 51' and sinkers S are lowered tosubstantially the position shown in FIGURE 3 and relatively long stitchloops may be immediately formed by raising the tube 30 and the sinkerhead 50 to substantially the position shown in FIGURE 4. Of course, thesinker head 50 may also be positioned at any intermediate position ormay be gradually moved from one position to another by the use of aconventional graduating mechanism, not shown, to change the length ofstitch loops being formed without upsetting the relationship of theneedle operating butts and the stitch drawing cams surrounding theneedle cylinder.

As has heretofore been stated, this invention may also be applied to aHernphill type machine wherein the length of stitch is regulated byvertical movement of the stitch cams while the needle cylinder is heldin a stationary position. The same problem is present in this typemachine because there is relative movement between the butts of theneedles carried by the needle cylinder and the stitch cams and verticalmovement of the stitch cams will change the operating relationship ofthe butts of the needles N and the stitch forming cams. In Hemphill typemachines, the sinker head normally is fixedly secured to the upper endof the needle cylinder and in order to apply the principles of thisinvention to a Hemphill type machine, it would be necessary to securethe stitch cams in a fixed position relative to the needle cylinder andindependently support the sinker head.

Although the problem of stitch length control has long been present incircular knitting machines, particularly where drastic stitch lengthregulation is required, there has been no practical solution to thisproblem prior to this invention. The present invention is the first torecognize the importance of maintaining the same relationship betweenthe operating butts of the needles and the stitch cams surrounding theneedle cylinder while also maintaining the same relationship between thehooks of the needles and the yarn feeding fingers. In the presentinvention, the positions of the needle cylinder, yarn feeding fingersand stitch cams have been fixed relative to each other and the length ofstitch loops is controlled by the height of the sinkers above the needlecylinder. Thus, the length of stitch loops may be controlled withoutchanging the operating relationship between the needles and the stitchcams or between the needles and the yarn feeding fingers.

In the drawings and specification there has been set forth a preferredembodiment of the invention and, although specific terms are employed,they are used in a generic and descriptive sense only and not forpurposes of limitation, the scope of the invention being defined in theclaims.

I claim:

1. In a circular knitting machine having a rotatable needle cylinder,vertically movable needles carried by said cylinder, and a sinker headencircling the upper ends of i said needles, stitch length control meanscomprising support means for supporting said sinker head independentlyof said needle cylinder, and pattern control means for elfectingrelative vertical movement between said needle cylinder and said sinkerhead during knitting.

2. In a circular knitting machine having a rotatable needle cylinder,vertically movable needles carried by said cylinder, and a sinker headencircling the upper ends of said needles, stitch length control meanscomprising support means for supporting said sinker head independentlyof said needle cylinder, and pattern control means operatively connectedto said support means for varying the position of said sinker headrelative to said needle cylinder during knitting.

3. A method of controlling the length of stitches formed by a circularknitting machine having a rotatable needle cylinder, vertically movableneedles carried by said cylinder, and a vertically movable sinker headencircling the upper ends of the needles which comprises the steps ofrotating the needle cylinder to form stitch loops of a predeterminedlength on the needles, increasing the length of stitches drawn by theneedles by raising the sinker head relative to the needle cylinder, anddecreasing the length of stitches drawn by the needles by lowering thesinker head relative to the needle cylinder.

4. A method of controlling the length of stitches formed by a circularknitting machine having a rotatable needle cylinder, vertically movableneedles carried by said cylinder and a vertically movable sinker headencircling the upper ends of the needles which comprises the steps ofrotating the needle cylinder to form stitch loops of a predeterminedlength on the needles, and then lengthing and shortening the stitchesdrawn by the needles by correspondingly raising and lowering the sinkerhead while maintaining the rotating needle cylinder in a fixed axialposition.

5. A method of controlling the length of stitches formed by a circularknitting machine having a rotatable needle cylinder, vertically movableneedles carried by said cylinder and a vertically movable sinker headencircling the upper ends of the needles which comprises the steps ofrotating the needle cylinder to form stitch loops of a predeterminedlength on the needles, and then varying the size of stitches formed bythe needles by correspondingly changing the vertical relationshipbetween the needle cylinder and the sinker head.

References Cited in the file of this patent UNITED STATES PATENTS679,281 Kilbourn July 23, 1901 726,178 Mayo Apr. 21, 1903 1,131,583Wilcomb Mar. 9, 1915 1,782,298 Grieve Nov. 18, 1930 1,817,116 WilliamsAug. 4, 1931 1,977,522 Mills Oct. 16, 1934 2,069,155 Lawson Jan. 26,1937 2,142,693 Lawson et al. Jan. 3, 1939 2,534,460 Lawson et al Dec.19, 1950

